Systemic lupus erythematosus (SLE) is a multi-organ autoimmune disease of unknown etiology that has many clinical manifestations. Almost any organ can be involved, but the most common manifestations are cutaneous, musculoskeletal and renal. SLE typically affects young women of childbearing potential between the ages of 15 to 44. The prevalence of SLE is 300,000 patients in the United States and 4 million patients worldwide, with an annual incidence of 15,000 in the United States alone.
The pathogenesis of SLE likely involves an array of components associated with both genetic and environmental factors. Disease susceptibility is influenced by genes related to immune response and the major histocompatability complex class I and II genes. Additional susceptibilitystems from interactions between the hormonal environment and the hypothalamo-pituitaryadrenalaxis. In addition, the development of SLE is associated with a defective immuneresponse which affects apoptotic cell clearance and immune complexes. The loss of immunetolerance, excess T cell help, defective B cell suppression, and the shifting of T helper 1 (Th1) to Th2 and Th17 immune responses leads to B cell hyperactivity and the production of pathogenicantibodies. External factors such as chemicals, drugs, ultraviolet light, diet and viruses also contribute to the onset of disease.
As SLE is a waxing and waning disease, it is often controlled with NSAIDs or low potency immunosuppression drugs (antimalarials and low dose corticosteroids) for milder symptomology (muscoskeletal manifestation, cutaneous manifestation and serositis). More prolonged and potent use of corticosteroids, as well as non-biologic disease modifying anti-rheumatic drugs (DMARDs), are standard treatments which are also available to treat those patients who exhibit major organ involvement. In conjunction with standard therapy, biological DMARD therapies exist to augment treatment for those patients with more extensive disease. Belimumab, a monoclonal antibody and B-lymphocyte stimulator-specific inhibitor, has recently been approved for use in conjunction with corticosteroids and other standard therapies for autoantibody-positive SLE. In addition, Rituximab, a B-cell depleter, is often used off-label as rescue medication for patients unresponsive to standard treatment. However, there still remains a need for prophylactic or therapeutic drugs that can be used to treat or prevent SLE.